The instant invention relates to the use of methoxysalicylaldehyde derivatives, preferably o-vanillin, and to methoxysalicylaldehyde derivatives, preferably o-vanillin, in combination with Trolox(copyright) or isopropanol, in protecting solid-state proteins from the effects of ionizing radiation. The invention further relates to radiation-resistant formulations comprising solid-state proteins and methoxysalicylaldehyde derivatives, preferably o-vanillin, and to radiation-resistant formulations comprising solid-state proteins and methoxysalicylaldehyde derivatives, preferably o-vanillin, in combination with Trolox(copyright) or isopropanol.
During the process of sterilizing pharmaceutical formulations, especially during terminal sterilization, it is critical that the formulation be protected against incidents detrimental to the activity and/or bioavailability of the active agent or agents comprising the formulation. For solid formulations not easily amenable to sterilization by standard protocols such as sterilizing filtration, alternative methodologies have been developed, including, for example, irradiation. Accordingly, the necessity of protecting certain labile synthetic and biological substrates from the effects of ionizing radiation during the sterilization process is well documented. See, for example, B. D. Reid, PDA J. Pharm. Sci. and Tech., 49 (2), 83-89 (1995), G. P. Jacobs, J. Biomaterials App., 10, 59-95 (1995), and N. G. S. Gopal, Radiat. Phys. Chem., 12, 35-50 (1978).
The methoxysalicylaldehyde derivative o-vanillin, also known as 3-methoxysalicylaldehyde, is a well-known anti-oxidant that has been employed in a variety of additional contexts, for example, as an enhancer of growth hormone release. See Clark, et al., U.S. Pat. No. 5,015,627.
The compound Trolox(copyright), also known as 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, has also been employed as an anti-oxidant as well as a radioprotectant in various contexts. For example, Trolox(copyright) and certain phenolic agents related thereto are useful in protecting solid-state polymers against radiation-induced oxidation. See Soebianto, et al., Polymer Degradation and Stability, 50, 203-210 (1995) and Klemchuk, Radiat. Phys. Chem., 41, 165-172 (1993). This compound has also been employed to ameliorate oxidation in foodstuffs. See, for example, Cort, U.S. Pat. No. 3,986,980. The compound has also been used to promote the repair of amino acid radicals derived from radiolytic protein degradation while in solution. See Bisby, et al., Biochem. Biophys. Res. Comm., 119, 245-251 (1984).
The present invention is directed to prophylactically protecting solid-state proteins from the effects of ionizing radiation by employing either a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde, in combination with the protein; a mixture of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid in combination with the protein; or a mixture of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde and isopropanol, in combination with the protein, prior to exposing the protein to ionizing radiation.
The invention further provides radiation-resistant pharmaceutical formulations comprising a protein and a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde; a protein and a combination of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; or a protein and a combination of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde and isopropanol.
The invention provides methods of protecting solid-state proteins from the effects of ionizing radiation which comprise combining the protein with a radiation-protecting amount of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde; radiation-protecting amounts of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; or radiation-protecting amounts of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde and isopropanol, prior to exposing the protein to ionizing radiation.
The invention further provides radiation-resistant pharmaceutical formulations comprising a protein and a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde; a protein and a combination of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; or a protein and a combination of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde and isopropanol.
The invention still further provides compositions comprising a combination of a methoxysalicylaldehyde derivative, preferably 3-methoxysalicylaldehyde, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, and for the use of such compositions in pharmaceutical formulations as a radioprotectant.